Ax Java Agent Observability

AxAgent Observability For Java

This skill helps an agent write Java code with the generated Ax package dev.axllm:ax. Use the generated package API, examples, and manifests; do not import TypeScript-only APIs unless you are editing the TypeScript package.

When To Use

• Inspect agent traces, runtime envelopes, usage, or action logs.
• Register the process-wide usage observer and attribute model calls by tenant, user, request, run, or feature.
• Attach callbacks for model/tool activity and runtime progress.
• Debug agent loops through generated package state and examples.

Package Facts

• Language: Java.
• Package: dev.axllm:ax.
• Package API docs: API.md and axir-api.json.
• Capability manifest: axir-capabilities.json.
• Runnable examples: examples/.
• Real network support: yes.
• Scripted no-key transport support: yes.
• Runtime profiles: javascript-quickjs, python-pyodide.

Core Pattern

AxAgent helper = Ax.agent("question:string -> answer:string", java.util.Map.of());
var out = helper.forward(llm, java.util.Map.of("question", "How should I proceed?"));

Centralized Usage Observer

Use the process-wide usage observer for application accounting across many agents, API routes, tenants, and users. Keep per-agent usage accessors for inspecting one agent instance after a run.

AxGlobals.setUsageObserver(usageQueue::add);
// Later: AxGlobals.setUsageObserver(null);

• The observer receives one normalized event for each completed chat or embedding call that reports provider usage. A fully consumed stream emits once; an unconsumed or cancelled stream may not emit.
• Events include the operation, AI/provider name, model, normalized tokens, streaming flag, optional usage context, and available session or remote request IDs.
• Attach usageContext in AI service options for stable application or environment defaults. Attach it in call or agent-forward option maps for tenant, user, request, run, and feature attribution.
• Per-call context overrides service defaults. Nested attributes are shallow-merged.
• The observer is process-wide, best-effort, and fail-open. Registering again replaces the previous observer. Clear it during test teardown or shutdown when appropriate.
• The observer runs on the request path. Production callbacks should synchronously enqueue into a bounded concurrent queue and return immediately, then persist or aggregate out of band. Use a shared durable pipeline across processes or serverless instances.
• Keep identifiers opaque and attributes low-cardinality. Do not attach prompts, responses, secrets, or other sensitive payloads.
• Calculate currency cost downstream against a versioned provider/model pricing table.
• Runnable provider example: src/examples/java/generation/UsageObserverExample.java.

Relevant API Surface

• AxAI: Ax.ai, AxCancellationToken, AxAIServiceAbortedError, Ax.getSupportedAIModels, OpenAICompatibleClient.CredentialRequest, OpenAICompatibleClient.CredentialProvider, AiClient.ownedWorkerFactory, AxChatSession, AxChatStream, OpenAICompatibleClient, OpenAIResponsesClient, GoogleGeminiClient, AnthropicClient, Map<String, Object>, AxUsageEvent, AxUsageObserver, AxGlobals.setUsageObserver, AxRuntimeHooks, AxRateLimitInfo, AxRateLimiter, AxTracer, AxMeter, AxGlobals, AxGlobals.setRateLimiter, AxGlobals.setTracer, AxGlobals.setMeter, AxBalancer, AxBalancerAdaptiveStrategy, AxBalancerStatsStore, AxInMemoryBalancerStatsStore, AxBalancerAdaptive.createRouteStats, AxBalancerAdaptive.updateRouteStats, AxBalancerAdaptive.sampleRouteHealth, MultiServiceRouter, ProviderRouter
• Agents And RLM: Ax.agent, AxAgent, AxAgent.addChildAgent
• Runtime Profiles: ProcessCodeRuntime, RuntimeCapabilities, RuntimeEnvelope, javascript-quickjs, python-pyodide

Guardrails

• Start from package examples for exact native syntax before inventing a new call shape.
• Use provider-api examples only when the user explicitly has provider credentials available.
• Use no-key examples for deterministic local checks and provider request mapping.
• Treat AxIR as the source of generated package truth: if package docs disagree with source code, update the compiler and regenerate packages.
• Do not copy repo-maintainer skills from tools/*/skills/ into user packages.